Morphology and properties of poly(ethylene terephthalate) and thermoplastic polyester elastomer blends modified in the melt by a diisocyanate chain extender and filled with a short glass fiber

The structural features and rheological, mechanical, and relaxation properties of poly(ethylene terephthalate) (PET) blends with 7–50 wt % polyester thermoplastic polyester elastomer (TPEE), a block copolymer of poly(butylene terephthalate) and poly(tetramethylene oxide), chemically modified by a diisocyanate chain extender (CE) and reinforced with 30% glass fibers (GF) were studied. The composites were obtained by reactive extrusion with a twin‐screw reactor–mixer with a unidirectional rotation of screws. The molecular–structural changes in the materials were judged against data provided by differential scanning calorimetry, scanning electron microscopy, relaxation spectrometry, and rheological analysis of the melts. Regardless of the TPEE concentration in the blends with GF‐reinforced PET, the addition of CE resulted in the growth of the indices of the mechanical properties at straining, bending, and impact loading and an increase in the melt viscosity. In addition, an increase in the average length of short GFs in the composites and an intensification of interphase adhesion in the polyester binder–GF surface system were observed. The introduction of CE promoted a slowdown in PET crystallization in the composites and intensified the interphase adhesion in the binder–GF system at temperatures higher and lower than the PET glass‐transition temperature. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45711.     

Effect of ortho‐diallyl bisphenol A on the processability of phthalonitrile‐based resin and their fiber‐reinforced laminates

Sluggish and narrow process window of phthalonitrile resin has tremendously limited their wide applications. In this work, a novel phthalonitrile containing benzoxazine (4,4′‐(((propane‐2,2‐diylbis (2H‐benzo [e] [1,3]oxazine‐6,3 (4H)‐diyl) bis(3,1‐phenylene))bis(oxy)) diphthalonitrile, BA‐ph) with ortho‐diallyl bisphenol A (DABPA) was investigated. The processing window of the BA‐ph/DABPA blends were found from 50°C to 185°C, which was significantly broader than that of the pure BA‐ph (120–200°C). The composites were prepared through a curing process involving sequential polymerization of allyl moieties, ring‐opening polymerization of oxazine rings and ring‐forming polymerization of nitrile groups. BA‐ph/DABPA/GF(glass fiber) composite laminates were prepared in this study, and the composite laminate with BA‐ph/DABPA molar ratio of 2/2 showed an outstanding flexural strength and modulus of 560 MPa and 37 GPa, respectively, as well as a superior thermal and thermo‐oxidative stability up to 408 and 410°C. These outstanding properties suggest that the BA‐ph/DABPA/GF composites are suitable candidates as matrices for high performance composites. POLYM. ENG. SCI., 56:150–157, 2016. © 2015 Society of Plastics Engineers     

Effect of surface functionalization on the properties (rheological,mechanical, and dielectric) and microtopography of PEN/CPEN‐f‐CNTs nanocomposites

Novel carboxylic poly(arylene ether nitrile)s (CPEN) functionalized carbon nanotubes (CPEN‐f‐CNTs) were successfully prepared by a simple and effective solvent–thermal route. The CPEN‐f‐CNTs were subsequently used as the novel filler for preparation of high performance poly(arylene ether nitrile)s (PEN) nanocomposites. The SEM characterization of the PEN nanocomposites revealed that the CPEN‐f‐CNTs present better dispersion and interfacial compatibility in the PEN matrix, which was confirmed by the linear rheological analysis (Cole–Cole plots) as well. Consequently, the improved thermal stability (increased initial and maximum decomposition temperature) and enhanced mechanical properties (tensile strength and modulus) were obtained from nanocomposites using CPEN‐f‐CNTs. More importantly, the PEN/CPEN‐f‐CNTs nanocomposites not only show a high dielectric constant but also have low dielectric loss. For example, a dielectric constant of 39.7 and a dielectric loss of 0.076 were observed in the PEN composite with 5 wt% CPEN‐f‐CNTs loading at 100 Hz. Therefore, the flexible PEN/CPEN‐f‐CNTs nanocomposites with outstanding mechanical, thermal and dielectric properties will find wide application in the high energy density capacitors. POLYM. COMPOS., 37:2622–2631, 2016. © 2015 Society of Plastics Engineers     

Novel high‐performance wave‐transparent aluminum phosphate/cyanate ester composites

Advanced wave‐transparent composites are the key materials for many cutting‐edge industries including aviation and aerospace, which should have outstanding heat resistance, low dielectric constant and loss as well as good mechanical properties. A novel kind of high‐performance wave‐transparent composites based on surface‐modified aluminum phosphate AlPO₄(KH‐550) and cyanate ester (CE) was first developed. The dielectric and dynamic mechanical properties of AlPO₄(KH‐550)/CE composites were investigated intensively. Results show that AlPO₄(KH‐550)/CE composites have decreased dielectric loss and higher storage moduli than pure CE resin; in addition, the composites with suitable AlPO₄(KH‐550) concentration remain the outstanding thermal property and low dielectric constant of pure CE resin. The reasons attributing to these results are discussed from the effects of AlPO₄(KH‐550) on the key aspects such as morphology, curing mechanism, and interfacial adhesion of composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of glass fiber‐multiwall carbon nanotube hybrid structures for high‐performance conductive composites

The conductive polyamide 66 (PA66)/carbon nanotube (CNT) composites reinforced with glass fiber‐multiwall CNT (GF‐MWCNT) hybrids were prepared by melt mixing. Electrostactic adsorption was utilized for the deposition of MWCNTs on the surfaces of glass fibers (GFs) to construct hybrid reinforcement with high‐electrical conductivity. The fabricated PA66/CNT composites reinforced with GF‐MWCNT hybrids showed enhanced electrical conductivity and mechanical properties as compared to those of PA66/CNT or PA66/GF/CNT composites. A significant reduction in percolation threshold was found for PA66/GF‐MWCNT/CNT composite (only 0.70 vol%). The morphological investigation demonstrated that MWCNT coating on the surfaces of the GFs improved load transfer between the GFs and the matrix. The presence of MWCNTs in the matrix‐rich interfacial regions enhanced the tensile modulus of the composite by about 10% than that of PA66/GF/CNT composite at the same CNT loading, which shows a promising route to build up high‐performance conductive composites. POLYM. COMPOS. 34:1313–1320, 2013. © 2013 Society of Plastics Engineers     

Mechanical and thermal enhancements of benzoxazine‐based GF composite laminated by in situ reaction with carboxyl functionalized CNTs

An easy and efficient approach by using carboxyl functionalized CNTs (CNT‐COOH) as nano reinforcement was reported to develop advanced thermosetting composite laminates. Benzoxazine containing cyano groups (BA‐ph) grafted with CNTs (CNT‐g‐BA‐ph), obtained from the in situ reaction of BA‐ph and CNT‐COOH, was used as polymer matrix and processed into glass fiber (GF)‐reinforced laminates through hot‐pressed technology. FTIR study confirmed that CNT‐COOH was bonded to BA‐ph matrices. The flexural strength and modulus increased from 450 MPa and 26.4 GPa in BA‐ph laminate to 650 MPa and 28.4 GPa in CNT‐g‐BA‐ph/GF composite, leading to 44 and 7.5% increase, respectively. The SEM image observation indicated that the CNT‐COOH was distributed homogeneously in the matrix, and thus significantly eliminated the resin‐rich regions and free volumes. Besides, the obtained composite laminates showed excellent thermal and thermal‐oxidative stabilities with the onset degradation temperature up to 624°C in N₂ and 522°C in air. This study demonstrated that CNT‐COOH grafted on thermosetting matrices through in situ reaction can lead to obvious mechanical and thermal increments, which provided a new and effective way to design and improve the properties of composite laminates. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Properties analysis of novel composites for space robots

Basing on modeling analysis of kinematics and dynamics of the innovational spacecraft‐space robots, increasingly complex space operations require the advanced composites to have excellent mechanical properties at high frequency. The novel powdery nitrile butadiene rubbers (P‐NBRs) are performed to fabricate the P‐NBRs/cyanate esters (P‐NBRs/CE) and P‐NBRs/glass fiber/CE (P‐NBRs/GF/CE) composites. Results show that the flexural and impact strength of the P‐NBRs/CE composites are increased firstly, but decreased with the excessive addition of P‐NBRs. The heat resistant properties of the P‐NBRs/CE composites are decreased with the increasing addition of P‐NBRs. However, the mechanical properties of P‐NBRs/GF/CE composites are decreased with the increasing addition of P‐NBRs. The dielectric constant and dielectric loss of the P‐NBRs/GF/CE composites are increased with the increasing addition of P‐NBRs. POLYM. COMPOS., 35:564–569, 2014. © 2013 Society of Plastics Engineers     

Influence of hybridization of glass fiber and talc on the mechanical performance of polypropylene composites

The effect of the hybridization of short glass fibers (GFs) and talc mineral filler on the tensile mechanical performance of injection‐molded propylene‐ethylene copolymer composites (PP_cop) with and without weld lines (WLs) was studied in this work. The fibrous reinforcement imparts high‐tensile stiffness and strength to the molding but originates a highly anisotropic composite. The negative effect of this anisotropy is even worse when WLs occur in the molding, as the high aspect ratio GFs tend to be oriented on the weak plane of the WL. Through hybridization of GF and talc, combined in different proportions, it is possible to obtain improved mechanical properties in comparison to the standard GF reinforced PP_cop composites. The combination of GF with talc was shown to be beneficial for the WL strength of PP_cop composites, once a synergism effect was achieved with the expected optimization of the fibers/particles packing efficiency of the hybrid reinforcement. At a given constant total reinforcement concentration, the experimental data of both tensile modulus and strength properties of the hybrid composites without WL were above the predictions derived from the estimated rule of mixtures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Glass fibers reinforced poly(ethylene 2,6‐naphthalate)/ethylene propylene diene monomer composites: Structure,mechanical, and thermal properties

Ethylene propylene diene monomer (EPDM) was blended with glass fibers (GFs)‐filled poly(ethylene 2,6‐naphthalate) (PEN) composites to improve the impact properties of PEN. The impact strength of PEN/EPDM/GF composite (PEN/EPDM = 60/40) was about 62 J/m, which was nearly four times higher than the PEN/GF composite without EPDM. At the same time, the tensile strength and flexural modulus were still maintained at considerable values since the GFs compensated the loss of mechanical properties of PEN by incorporation of EPDM. The scanning electron microscopy results showed that the GFs were orientated and homogenously dispersed in the PEN matrix and, after incorporation of EPDM, the surface of GFs were covered by a matrix layer which became coarse and thick with increasing EPDM content. The dynamic mechanical analysis results showed the poor compatibility between PEN and EPDM. The thermal gravimetric analysis revealed that the PEN matrix protected the dispersed EPDM domains, resulting in an increased maximum peak temperature (T_max) of the EPDM phase. At last, the results of differential scanning calorimetry analysis indicated that incorporation of EPDM led to an increase in crystallization rate and improvement in crystallization temperature. POLYM. COMPOS., 35:939–947, 2014. © 2013 Society of Plastics Engineers     

Flammability and thermomechanical properties of dianhydride‐modified polybenzoxazine composites reinforced with carbon fiber

Composites based on carbon fiber (CF) and benzoxazine (BA‐a) modified with PMDA were investigated. The flammability of the carbon fiber composites was examined by limiting oxygen index (LOI) and UL‐94 vertical tests. The LOI values increased from 26.0 for the CF/poly(BA‐a) composite to 49.5 for the CF‐reinforced BA‐a/PMDA composites as thin as 1.0 mm and the CF‐reinforced BA‐a/PMDA composites were also achieved the maximum V‐0 fire resistant classification. Moreover, the incorporation of the PMDA into poly(BA‐a) matrix significantly enhanced the T_g and the storage modulus (E') values of the CF‐reinforced BA‐a/PMDA composites rather than those of the CF/poly(BA‐a). The T_g values and storage moduli of the obtained CF‐reinforced BA‐a/PMDA composites were found to have relatively high value up to 237°C and 46 GPa, respectively. The CF‐reinforced BA‐a/PMDA composites exhibited relatively high degradation temperature up to 498°C and substantial enhancement in char yield with a value of up to 82%, which are somewhat higher compared to those of the CF/poly(BA‐a) composite, i.e., 405°C and 75.7%, respectively. Therefore, due to the improvement in flame retardant, mechanical and thermal properties, the obtained CF‐reinforced BA‐a/PMDA composites exhibited high potential applications in advanced composite materials that required mechanical integrity and self‐extinguishing property. POLYM. COMPOS., 34:2067–2075, 2013. © 2013 Society of Plastics Engineers     

Preparation and properties of maleimide‐functionalized hyperbranched polysiloxane and its hybrids based on cyanate ester resin

A new hyperbranched polysiloxane containing maleimide (HPMA) was synthesized through the reaction between N‐(4‐hydroxyphenyl) maleimide and 3‐glycidoxypropyltrimethoxysilane, which was then used to prepare cyanate ester (CE) resin‐based hybrids (coded as HPMAx/CE, where x is the weight fraction of HPMA in the hybrid). The curing behavior of uncured hybrids and the typical properties (impact strength and dielectric properties) of cured hybrids were systemically investigated. Results show that the performance of hybrids is greatly related with the content of HPMA. Hybrids have obviously lower curing temperature than CE, overcoming the poor curing characteristics (higher curing temperature and longer curing time) of neat CE, for example, the curing peak temperature of HPMA20/CE is about 65°C lower than that of CE. In the case of cured resin and hybrids, the hybrids exhibit decreased dielectric constant and loss than CE resin; moreover, the former also exhibits lower water absorption than the latter. Specifically, the dielectric loss of HPMA15/CE hybrid is only about 27% of that of neat CE resin. In addition, the hybrids with suitable contents of HPMA have significantly improved impact strengths. The overall improved properties suggest that HPMAx/CE hybrids have great potential in applications needing harsh requirements of curing feature, dielectric properties, and toughness. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Investigation on curing reaction of phthalonitrile resin with nanosilica and the properties of their glass fiber-reinforced composites

In this work, Phthalonitrile containing benzoxazine (BA-ph) and Bisphenol A based cyanate ester (CE) were chosen as the matrix resin. Various amount of nano-SiO₂ was incorporated into BA-ph/CE and their glass fiber-reinforced composite laminates were fabricated. Curing reaction and processability of BA-ph/CE/SiO₂ blends were studied by differential scanning calorimetry and dynamic rheological analysis. Results showed that BA-ph and CE exhibited good processability and curing reaction of BA-ph/CE was not obviously affected by SiO₂. Scanning electron microscope images of the composites showed that SiO₂ particles were well dispersed in BA-ph/CE matrix. Moreover, SiO₂ could act as physical crosslinking points and diluent in matrix as well as between the glass fibers to improve the mechanical properties of composite laminates. As the results of dynamic mechanical analysis and thermogravimetry analysis, composite laminates possessed satisfactory T_g and good thermal stability. With incorporation SiO₂ particles into matrix resin, dielectric constant and dielectric loss of BA-ph/CE/SiO₂/GF composites were increased and showed frequency dependence.     

Mechanical,thermal, electrical,and interfacial properties of high‐performance bisphthalonitrile/polyarylene ether nitrile/glass fiber composite laminates

Bisphthalonitrile (BAPh)/polyarylene ether nitrile end‐capped with hydroxyl groups (PEN‐OH) composite laminates reinforced with glass fiber (GF) have been fabricated in this article. The curing behaviors of BAPh/PEN‐OH prepolymers have been characterized by differential scanning calorimetry and dynamic rheological analysis. The results indicate that with the introduction of PEN‐OH the curing temperature of BAPh has decreased to 229.6–234.8°C and BAPh/PEN‐OH prepolymers exhibit large processing windows with relatively low melt viscosity. The BAPh/PEN‐OH/GF composite laminates exhibit tensile strength (272.4–456.5 MPa) and modulus (4.9–10.0 GPa), flexural strength (507.1–560.9 MPa), and flexural modulus (24.0–30.4 GPa) with high thermal (stable up to 538.3°C) and thermal stabilities (stable up to 475.5°C). The dielectric properties of BAPh/PEN‐OH/GF composite laminates have also been investigated, which had little dependence on the frequency. Meanwhile, scanning electron microscopy results show that the BAPh/PEN‐OH/GF composite laminates display excellent interfacial adhesions between the matrix and GFs. Herein, the BAPh/PEN‐OH matrix can be a good matrix for high‐performance polymeric materials and the advanced BAPh/PEN‐OH/GF composite laminates can be used under high temperature environment. POLYM. COMPOS., 34:2160–2168, 2013. © 2013 Society of Plastics Engineers     

A novel hybrid functional nanoparticle and its effects on the dielectric,mechanical, and thermal properties of cyanate ester

A novel hybrid functional nanoparticle (denoted POSS‐MPS) was synthesized by aminopropyl‐functionalized mesoporous silica (AP‐MPS) with glycidyl polyhedral oligomeric silsesquioxane (G‐POSS). The G‐POSS was employed as molecular caps to envelop the MPS and improve the interaction with the polymer matrix. The POSS‐MPS hybrids were designed to improve the properties of cyanate ester (CE) without affecting its inherent properties. The POSS‐MPS/CE composites exhibited excellent improvement in dielectric properties, mechanical properties, and thermal properties due to increase of voids volume in the composites and reinforcement of interface interaction between organic and inorganic phase. The dielectric constant (κ) and loss factor (tan δ) of composites with 4 phr of POSS‐MPS reduced to 2.78 and 0.008 in comparison to pure CE with the value of 3.27 and 0.012, respectively. Moreover, the composites exhibited 14.3, 4.9, 57.5, and 8.7% enhancement in flexural strength, flexural modulus, impact strength, and glass transition temperature (T_g) in comparison to pure CE, respectively. The results manifested that introduction of POSS‐MPS into CE exhibited toughening and reinforcing effects on the composites. POLYM. COMPOS., 37:2142–2151, 2016. © 2015 Society of Plastics Engineers     

Resin transfer molding of natural fiber reinforced polybenzoxazine composities

Kenaf fiber is incorporated in a polybenzoxazine (PBZX) resin matrix to form a unidirectionally reinforced composite containing 20 wt% fiber by a resin transfer molding technique. Two types of benzoxazine monomer are synthesized and used as resin mixtures: Benzozazines based on bisphenol‐A/aniline (BA‐a) and phenol/aniline (Ph‐a). The effects of varying BA‐a:Ph‐a ratio in the resin mixture and curing conditions on mechanical properties of pure PBZX resin and kenaf/PBZX composites are studies. The Flexural strength of the pure PBZX resin increases with increasing ratio of BA‐a:Ph‐a, curing temperature and curing time, but the impact strength increases only slightly. PBZX resin has lower water absorption and higher flexural modulus, when compared with unsaturated polyester (UPE) resin. PBZX composites with 20 wt% fiber content have lower flexural and impact strengths, but higher moduli compared with UPE composites with the same fiber content.     

Preparation and characterization of quartz‐fiber‐cloth‐reinforced,polymerization‐of‐monomer‐reactant‐type polyimide substrates with a high impact strength

A series of novel quartz‐fiber‐cloth‐reinforced polyimide substrates with low dielectric constants were successfully prepared. For this purpose, the A‐stage polyimide solution was first synthesized via a polymerization‐of‐monomer‐reactant procedure with 2,2′‐bis(trifluoromethyl)benzidine and 3,3′,4,4′‐oxydiphthalic anhydride as the monomers, and cis?5‐norbornene‐endo‐2,3‐dicarboxylic anhydride as the endcap. Then, an A‐stage polyimide solution (TOPI) was impregnated with quartz‐fiber cloth (QF) to afford the prepregs, which were thermally molded into the final substrate composites. The influence of the curing temperature and the resin content on the mechanical properties of the composite were examined. The composites exhibited a high glass‐transition temperature over 360°C, a low and steady dielectric constant below 3.2 at a test frequency of 1–12 GHz, and a volume resistance over 1.8 × 10¹⁷ Ω cm. Meanwhile, they also showed a high mechanical strength with flexural and impact strengths in ranges 845–881 MPa and 141–155 KJ/m², respectively. The excellent mechanical and thermal properties and good dielectric properties indicated that they are good candidates for integrated circuit packaging substrates. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42358.     

Synthesis of epoxy‐functionalized hyperbranched poly(phenylene oxide) and its modification of cyanate ester resin

High curing temperature is the key drawback of present heat resistant thermosetting resins. A novel epoxy‐functionalized hyperbranched poly(phenylene oxide), coded as eHBPPO, was synthesized, and used to modify 2,2′‐bis (4‐cyanatophenyl) isopropylidene (CE). Compared with CE, CE/eHBPPO system has significantly decreased curing temperature owing to the different curing mechanism. Based on this results, cured CE/eHBPPO resins without postcuring process, and cured CE resin postcured at 230°C were prepared, their dynamic mechanical and dielectric properties were systematically investigated. Results show that cured CE/eHBPPO resins not only have excellent stability in dielectric properties over a wide frequency range (1–10⁹Hz), but also show attractively lower dielectric constant and loss than CE resin. In addition, cured CE/eHBPPO resins also have high glass transition temperature and storage moduli in glassy state. These attractive integrated performance of CE/eHBPPO suggest a new method to develop high performance resins. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Morphology,thermal and mechanical properties of glass fiber‐reinforced crosslinkable poly(arylene ether nitrile)

Crosslinkable poly(arylene ether nitrile)/glass fiber (PEN/GF) composites with high thermal stabilities and mechanical properties were prepared by a economically and environmentally viable method of melt extrusion and injection molding. The feasibility of using PEN/GF composites was investigated by evaluating its morphological, rheological, thermal, and mechanical properties. The morphology shows a good dispersion and strong interfacial interaction between PEN and GF. Thermal studies reveal that the thermal stabilities of PEN/GF are improved significantly with increase of GF content. Mechanical investigation manifested that GFs have strengthening effect (increase in flexural, tensile, and impact strength) on the mechanical performance of PEN composites. Most importantly, crosslinking reaction of PEN/GF composites can further improve their mechanical performances, because a couple of GFs are agglomerated by thermal motion and strong interfacial adhesion and the local agglomeration does not break the global uniform distribution. This work shows that both the enhancement of GF content and the crosslinking reaction of PEN/GF composites are two key factors influencing the thermal and mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Glass fiber reinforced and β‐nucleating agents regulated polypropylene: A complementary approach and a case study

A two‐step process for preparing glass fibers (GFs) reinforced β‐nucleated PP composites was designed and developed. The complementary approach combined GFs reinforcement and β‐nucleating agents regulation using N,N′‐dicyclohexyl‐2,6‐napthalene‐dicarboxamide (TMB‐5) in the presence of maleic anhydride grafted polypropylene (PP‐g‐MA) through extrusion blending. The influence of TMB‐5 and GFs on the mechanical properties and crystallization behavior of PP was studied by mechanical test, wide‐angle X‐ray diffraction, differential scanning calorimetry, and scanning electron microscopy. A distinct complementary effect of GFs and β‐nucleating agent TMB‐5 on mechanical properties and crystallization behavior of PP was observed. Results showed that addition of 20 wt % GFs and 0.1 wt % TMB‐5 into PP matrix with the two‐step process could lead to significant increase to its mechanical properties: specifically 64.8% improvement in tensile strength, 107.1% enhancement in flexural modulus, and 167.7% increasement in notched impact strength compared to that of neat PP. Furthermore, with the combination of TMB‐5 and GFs, not only led to promoted interfacial adhesion, but also significantly improved overall comprehensive mechanical properties. The complementary process provided an alternative approach for the development of PP with balanced toughnesss and stiffness. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45768.     

From brittle-to-ductile fracture of polymer composites: The incorporation of energy dissipation mechanisms by carbon nanotubes-based multilayered interface

Interfaces can have a great influence on the behavior and properties of polymer composites. In this work, the versatile and low-cost layer-by-layer technique was used for depositing layers of poly(diallyldimethylammonium chloride) (PDDA) and poly(sodium 4-styrenesulfonate) (PSS) containing oxidized multiwalled carbon nanotubes (MWCNT-COOH) on the surface of woven glass fibers (GFs); and polypropylene composites containing the modified GFs were prepared by compression molding. The effect of this novel hybrid multilayered interface on the mechanical properties and fracture behavior of the GF reinforced polymer (GFRP) composites was systematically investigated. For that, in situ tensile tests of the composites were monitored by using the high-resolution phase-contrast tomography. We found that the GFRP composites with multilayered interface (GFRP multilayered) exhibited exceptional increase in ductility and fracture toughness (about 25 and 130%, respectively), when compared to the composites without interfacial modification (GFRP untreated). Whereas the failure characteristics of the GFRP-untreated composites were typical of fragile systems (mainly, delamination), the GFRP-multilayered exhibited additional toughening mechanisms such as crazing and fibrillation as result of the enhanced interfacial adhesion. Our results clearly indicate that the multilayered interface of PDDA/PSS/MWCNT-COOH led to a more efficient load transfer from the matrix to the GFs, culminating with the brittle-to-ductile transition in the failure mode.